1. Field of the Invention
This invention is directed to a beverage fluid flow controller for controlling the flow of beverage syrup and carbonated water to a dispensing valve, such flow rate being adjusted against variations in supply and uniformly responsive to dispensing valve operation.
2. Description of the Prior Art
The prior art includes soft drink dispensing systems where a carbon dioxide pressure tank provides carbon dioxide gas to pressurize a syrup tank and to provide carbon dioxide to carbonate water. A dispensing valve receives both of these soft drink liquid components and simultaneously dispenses and mixes them when the dispensing valve is opened. Welty U.S. Pat. No. 3,468,137 discloses such a system. In attempts to assure that the quality of the drink is maintained under varying operating conditions, such as changes in the viscosity of the syrup or changes in the pressure of the carbon dioxide gas, a flow controller valve such as that shown in Welty U.S. Pat. No. 3,335,749 is employed in the pressurized syrup control line in an attempt to maintain a constant syrup flow rate independent of variations in supply pressure. Such flow controller valves generally have not performed satisfactorily over all desired ranges of supply pressure and, further, have suffered from other insufficiencies discussed herein.
Temperature and pressure variations cause variations in the pressure in the syrup and carbonated water flow line, resulting in non-uniformity of flow and consequent lack of drink uniformity which is objectionable to the consumer. When the syrup is below limits, the beverage is too thin; when the syrup is in excess of desired limits, the beverage is too syrupy and sweet. Furthermore, in this case, too much syrup results in a beverage which is expensive to the proprietor. Thus, for proper quality control and economy in the provision of the right quantity of syrup, the flow rate must be controlled in accordance with supply pressure so as to compensate for variations in such pressure, thereby preventing variations in flow rate due to variations in supply pressure.
Furthermore, many operators of the hand-operated dispensing valve turn the valve on and off rapidly, particularly during the last stage of the glass-filling operation in an attempt to obtain a full glass without foaming over. The flow controllers of the prior art respond to such rapid variations in actual flow by severely fluctuating in the quality of their flow control function. In some cases, relatively large quantities of syrup which may be called "slugs" are caused to be ejected forcefully from the flow controller into the flow line so as to be dispensed from the dispensing valve in a non-uniform ratio to the carbonated water, thus excessively strengthening the syrup-to-water ratio beyond tolerable limits as well as in a non-uniform manner. This condition is believed to occur generally in the flow controllers of this art because their functional control of flow rate is dependent upon a relatively constant flow condition such as, for example, merely compensating for slow changes in supply pressure without provision for rapid accommodation to rapid variations in actual flow conditions. Thus, for example, the flow controllers of the prior art do not take into account the problems which arise with rapid on and off operation of the dispensing valve downstream from the flow controller.